I want to develop my own Arudino UNO board following below Article.
I cannot find interfacing for USB, any idea how this can be done ?
Use a USB to TTL Serial cable or board, sometimes called an FTDI cable.
I would suggest you to use the UNO board to burn the program. You have too buy a FTDI breakout board which will cost you around 14-15$.
Other USB interface options are:
CP2102 modules found on e-bay.
Look for units that have holes along the side where some signals are brought out. You will do a simple mod to cut the RST trace going to the end header pin and wire the pin to the DTR hole instead. This will allow software resets during downloads.
Having USB interface capability can be very handy during sketch debugging.